With the development of radio multimedia services, on the one hand, demands of people for high data rate and user experience are increasing, and on the other hand, demands of people for knowing and communicating with a person or thing nearby, namely for Proximity Services (ProSe) or sidelink are also increasing due to application scenarios such as public security, social networking, short-range data sharing and local advertising. As a result, the requirement on the system capacity and coverage of a traditional cellular network may be increased.
However, a traditional cellular network mainly based on base stations is obviously restricted in terms of high data rate and ProSe support. Under the background of this demand, a Device-to-Device (D2D) technology representative of a new direction for future communication technology development emerges. Application of the D2D technology can alleviate burdens on a cellular network, reduce the battery power consumption of a User Equipment (UE), increase data rate, and improve the robustness of a network infrastructure, thereby well meeting requirements for the aforementioned high data rate services and ProSe.
FIG. 1 is a diagram illustrating direct discovery or communication between D2D UEs. As shown in FIG. 1, the D2D technology may work in a licensed band or unlicensed band to allow a plurality of UEs (also called as D2D UEs) supporting a D2D function to perform direct discovery or direct communication in the presence or absence of a network infrastructure. At present, there are mainly three D2D application scenarios. In a first D2D application scenario, UE1 and UE2 perform data interaction under the coverage of a cellular network, and user plane data does not pass through the network infrastructure, as shown in Mode 1 of FIG. 1. In a second D2D application scenario, for a UE in a weak-coverage or out-of-coverage region (e.g., UE4 under transmission of a first UE), the UE4 with poor signal quality is allowed to communicate with the network through UE3 under network coverage, so that coverage of an operator can be expanded and capacity of the network can be improved, as shown in Mode 2 of FIG. 1. In a third D2D application scenario, when an earthquake occurs or in an emergency, if the cellular network cannot work normally, direct communication between devices is allowed, for example, UE5, UE6 and UE7 may perform one-hop or multi-hop data communication in the control plane and the user plane without passing through the network infrastructure.
The D2D technology may include a D2D discovery technology and a D2D communication technology. The D2D discovery technology refers to a technology for determining whether a first UE is in proximity to a second UE. D2D UEs may discover each other by transmitting or receiving a discovery signal. The D2D communication technology refers to a technology where some or all communication data may be directly transmitted between D2D UEs without passing through the network infrastructure. An interface used by a UE for directly communicating with another UE through the D2D technology may be a PC5 interface, and an interface used by a UE for communicating with a serving base station may be a Uu interface.
Before performing D2D discovery or D2D communication, the D2D UEs may need to acquire their respective corresponding radio resources first. According to the progress of an existing 3rd Generation Partnership Project (3GPP) standard conference, there are two resource allocation manners for radio resource acquisition in both D2D discovery and D2D communication. In a first resource allocation manner, resources may be acquired in a resource allocation acquisition manner based on UE selection. In a second resource allocation manner, a base station (e.g., an evolved NodeB (eNB)) schedules and allocates dedicated resources for D2D discovery or D2D communication to a UE. In the first resource allocation manner, a base station or a system may pre-allocate a D2D resource pool, a UE participating in D2D discovery or D2D communication or a Proximity Service based UE (ProSe UE) may monitor the resource pool, and radio resources may be acquired in a resource allocation acquisition manner based on UE selection. In the second resource allocation manner, the base station may allocate appropriate radio resources to the ProSe UE according to the request of the ProSe UE.
FIG. 2 is a diagram of a relay system. As shown in FIG. 2, a relay, serving as a UE, may communicate with a network using an existing Long Term Evolution (LTE) manner, and may also communicate with UEs (e.g., UE1 and UE2 in the figure) out of coverage by using a D2D manner, including D2D discovery and/or D2D communication. If the UEs out of coverage transmit data to a base station through the relay, these UEs are called remote UEs. According to the existing manner, the UEs out of coverage may acquire resources only in a resource allocation acquisition manner based on UE selection. If multiple D2D UEs exist near the relay and select resources by themselves without cooperation, data transmitted to the relay by the remote UEs may be interfered by other UEs or may bring interference to transmission of other UEs, thereby resulting in that the data from the remote UEs cannot be correctly received.
Any effective solution has not been proposed yet at present for a problem existing in data transmission and/or reception caused by a resource acquisition manner.